Fluid flow control system

ABSTRACT

A system for controlling the rate of fluid flow through a main fluid pressure operated valve that is controlled by a pilot flow control valve. The pilot valve includes a movable wall responsive to pressure differential in the main system and also includes relatively movable seat and plug members that control flow of control fluid associated with the main valve, one of the members being activated by the movable wall to vary the relative positions of the members, and one of said members being movable by a manual means to vary the relative position of the members whereby the flow rate through the main valve at a given supply pressure may be varied. The invention also includes the arrangement of the pilot valve in which the manual means is mechanically and non-yieldingly connected to one of the valve elements of the pilot valve for positive movement thereof by the manual means.

United States Patent [191 Millar et al. f

1 June 28, 1974 [5 1 I'FLUID FLOW CONTROL SYSTEM [75] Inventors: JamesS. Millar, Fountain Valley;

Glenn W. Henderson, Tustin, both of Calif.

[73] Assignee: Parker-Hannifin Corporation,

Cleveland,0hio

[22] Filed: May 11, 1973 [21] Appl. No.: 359,464

52 user. 137/220, 137/486 51 Int.Cl. ..G05d 7/03,

[58] Field of Search 137/486, 487, 220, 492.5, 137/485, 488, 489, 489.5,502

[56] v References Cited UNITED STATES PATENTS 3,22l,764

12/1965 Elbogen et al 137/486 X Primary Examinerl-lenry T. KlinksiekeAssistant ExaminerRobert J. Miller Attorney, Agent, or Firm-John N.Wolfram [5 7] 7 ABSTRACT A system for controlling the rate of fluid flowthrough a main fluid pressure operated valve that is controlled by apilot flow control valve. The pilot valve includes a movable wallresponsive to pressure differential in the main system and also includesrelatively movable seat and plug members that control flow of controlfluid associated with the main valve, one of the members being activatedby the movable wall to vary the relative positions of the members. andone of said members'being movable by a manual means to vary the relativeposition of the members whereby the flow rate through the main valve ata given supply pressure may be varied. The invention also includes thearrangement of the pilot valve in which the manual I means ismechanically and non-yieldingly connected to one of the'valve elementsof the pilot valve for positive movement thereof by the manual means.

l qaim vDraw n F g es.

FLUID FLOW CONTROL SYSTEM BACKGROUND OF THE INVENTION In previoussystems for controlling flow of fluid, such as systems for filling anaircraft fuel tank from a ground supply, it is known to utilize a fluidpressure operated main valve controlled by a pilot valve for deliveringfluid at a predetermined rate of flow according to selecteddifferentials in pressure at selected parts of the system and to providea means for changing the setting of the pilot valve for changing theflow rate through the main valve. Two such previous arrangements areshown in US. letters Pat. Nos. 1 2,868,226 and 3,177,891. However, suchprevious systems employ a manually adjustable spring for varying thesetting of the pilot valve and thus are dependent upon the accuracy andstability of the spring for making adjustments in the 7 pilot valvesetting and hence in the main valve flow rate.

SUMMARY OF THE INVENTION bers which when engaged prevent. flow throughthe pilot valve and when not engaged are relatively positionable to varythe flow through the pilot valve, which in turn causes the flow throughthe main'valve to vary. The manually adjustable means is directly, thatis, nonyieldingly connected to one of the pilot valve movable members tovary its position in a positive or'fixed manner.

DETAIL DESCRIPTION FIG. 1 is a schematic view of the system.

FIG. 2 is a longitudinal cross section through the pilot flow controlvalve.

FIG. 3 is an external partial view of the pilot flow control valve.

The system includes a main valve. having an inlet port 11 connectable toa supply of liquid fuel and an outlet port 12 connectable unto a conduit13 leading to Pilot valve 36 has'a high pressure port 43 connected by aconduit 44 with the inlet side 14 of venturi 15 and has a low pressureport 45 connected by conduit 46 with throat 16 of the venturi. Anadjustable needle type restricter valve 47 is in a conduit 48 thatconnects conduits 44 and 46.

Pilot valve 36 has a body 50 to which is attached a cap 51 that clamps aflexible diaphragm 52 thereto. The diaphragm divides a hollow spacebetween the body and cap into a high pressure chamber 53 thatcommunicates with port 43 and a low pressure chamber 55 thatcommunicates with low pressure port 45.

the inlet 14 of a venturi tube 15 that has a throat l6 and I an outlet17 connectable to a conduit 18 which leads to a nozzle, not shown, forattachment to an aircraft fuel tank to 'be filled.

Main valve 10 has a valve chamber 22 in which a cup shaped member 23 ismounted by means of several circumferentially spaced spider elements 24.A main valve member 26 is slidably mounted within cup shaped member 23and is sealed relative thereto by a packing ring 27 so that the interiorof valve member 26 and cup shaped member 23 form a pressure chamber 29.Valve 10 includes a valve seat 31 against which valve member 26 isnormally pressed by a spring 32. A passage or conduit 33 passing throughone of the spider elements 24 connects chamber 29 with an inlet port 35of a pilot flow control valve 36 and another conduit 37 connects anoutlet port 38 of pilot valve 36 with the downstream or outlet side ofmain valve 10. A bypass passage 40 having a restriction 41 thereinconnects main valve inlet 11 with passage 33.

Diaphragm 52 is clamped to a valve plug member 57 by a threaded nut 58and a spring 59 urges valve plug 57 toward cap 51.

Body 50 has a bore 61 in which valve plug 57 is slidably mounted andsealed by a packing 62. Bore 61 leads to a first counterbore 63 which inturn leads to a second and slightly larger counterbore 64 having athreaded entrance 65.

A valve seat member 67 has a threaded connection with threaded portion65 and has an inner cylindrical portion 68 slidable within bore 63 andsealed relative thereto by a packing 69. Seat member 67 has anothercylindrical portion 71 slidable within counterbore 64 and sealed thereinby packing 72. Intermediate valve plug portions 68 and 71 is a reduceddiameter portion 72 which has several crossholes 73 therein whichcommunicate inlet port 35 with a blind bore 74 which forms a valve seat75 at its outer end that is cooperable with a tapered seat 76 on valveplug 57 for controlling flow of fluid between inlet port 35 and outletport 38.

The outer end of valve plug 67 has a tapered wedge fit at 78 witha nob79 and is locked thereto bya screw 80. At this end, body 50 has anextension 81 received within a bore 82 of knob 79 and also has anexternal groove 83 into which projects the inner end of a screw 84threaded through the wall of nob 79. Clamped by screw 84 to nob 79 is acircular band 85 having circumferentially spaced indicia 86 thereon. Apointer 87 is clamped to body 50 by a screw 88 for cooperation withindicia 86.

DESCRIPTION With main'valve inlet 11 connected to a source of supply andconduit 18 connected to a nozzle which in turn is connected to anaircraft tank to be filled, nob 79 is rotated until pointer 87 registerswith the particular indicia 86 corresponding with the desired rate offlow through the main valve, which may be expressed in gallons perminute or any other desired manner. Rotation of nob 79 will cause valveseat member 66 to move axially within body 50 by virtue of threadedconnection 65 for axially positioning valve seat 75 a predetermineddistance from tapered seat 76 of valve plug 57, the latter at this timebeing held in its extreme upward position by spring 59. The system pump,not shown, is now turned on to deliver liquid fuel to main valve inletport 11. The pressure of this fuel opens main valve member 26 and thefuel passes through main valve 10, conduit 13, venturi 15 and conduit 18for delivery to the aircraft tank.

26 has an area defined by packing 27 that is larger than an area on itsouter face defined by valve seat 31. Because pressure fluid may beexhausted from pressure chamber 29 through pilot valve 36 faster than itcan pass through restriction 41, the pressure in chamber 29 at this timeis lower than the pressure in valve inlet port 11 and main valve 26remains open.

As the fluid passes through venturi 15, it has a higher pressure atventuri inlet 14 than at throat 16. The higher pressure is transmittedto the upper side of diaphragm 52 via conduit 44 and high pressure port43 while the lower pressure from throat 16 is transmitted to the lowerside of diaphragm 52 via conduit 46 and low pressure port 45.

When main valve member 26 has opened sufficiently wide to provide theflow rate preselected with nob 79, the differential in pressures atventuri inlet 14 and throat 16 will be such that this differentialacting on pilot valve diaphragm 52 against spring 59 will move valveplug 57 to a position relative to valve seat 75 so that the pilot flowof fluid from conduit 33 to conduit 37 will maintain a particularpressure within chamber 29 to position valve member 26 relative to valveseat 31 for maintaining the desired fiow rate through the system.

Changing of nob 79 to a different selected flow rate causes valve seat75 to assume a differential axial position within bore 63 and hence theamount of opening relative to plug seat 76 becomes changed when thelatter has a fixed position corresponding to the given pressuredifferential between the inlet and throat of the venturi. Thus, nob 79provides a manual means for selecting the desired flow rate through thesystem and accomplishes this by a direct mechanical connection betweennob 79 and valve seat 75 so that the axial movement of valve seat 75 ispositive and directly related to rotary movement of nob 79. So thatbacklash or loose? ness due to manufacturing tolerances of threadedconnection 65 will not cause inaccuracies in the flow rate settings,valve seat member 66 is provided with an effective area defined by thedifference in diameters of bores 63, 64 whereby fluid pressure withinbore 64 constantly acts downwardly upon this effective area to maintainmember-67 in a downward position relative to the clearance in threadedsection 65.

Instead of providing the threaded means for adjusting the axial positionof seat 75 within bore 63, an alternate method would be to provide a twopart pilot valve plug 57 with the parts being axially adjustablerelative to each other. However, such an arrangement would be morecomplicated and adjustment of seat 75 as herein disclosed is preferred.

Also, instead of a venturi for providing a differential pressure thatvaries with the flow rate and is transmitted to the pilot control valve,any other type of pressure differential device may be employed. One suchother device could be an orifice plate in the flow path with the highpressure conduit 44 connected to the upstream side of the orifice plateand conduit 46 connected to the downstream side. Although the venturi 15as shown on the downstream side of valve 10, it, or some other form ofpressure differential device, could be located on the upstream side.

I claim:

l. A flow control system comprising a main valve with a housing havingan inlet port, an outlet port and a pressure chamber, a valve memberhaving one area exposed to the inlet port and an opposite and largerarea exposed to said pressure chamber whereby said valve member is movedtoward open and closed positions according to predetermineddifferentials in pressures of fluid in said inlet port and pressurechamber, a differential pressure device on one side of said main valveand connected thereto so that fluid passing through the main valve alsopasses through the device, said device having means to create a lowerpressure in the outlet side thereof than in the inlet side, a flowcontrol valve having a pressure responsive movable wall with one side ofthe wall connected to the inlet side of said device and an opposite'side connected to said outlet side, a pilot valve actuated by saidmovable wall, conduit means connecting an upstream side of the pilotvalve to the upstream side of the main valve and to said pressurechamber, and a conduit connecting the downstream side of the pilot valveto the downstream side of the main valve, said pilot valve including aseat member and a plug member, said members being relatively movable forcontrolling flow between said pressure chamber and said outlet port, andadjusting means for directly moving one of said members relative to theother member for varying the amount of opening between said members whenthe movable wall is in a predetermined position.

2. The system of claim 1 in'which said pressure differential device isdownstream of the main valve.

3. The system of claim 1 in which the pilot valve members are eachindependently movable of the other.

4. The system of claim 1 in which the seat member has a flow passagetherethrough openable and closeable by the plug member, the seat memberis connected to the adjusting means for movement thereby and the plugmember is connected to said movable wall for movement thereby. 1

5. The system of claim 1 in which the pressure differential devicecomprises a venturi.

6. The system of claim 1 in which there is a means for adjusting thepressure differential transmitted by the pressure differential device tosaid pilot control valve.

7. The system of claim 1 in which the adjusting means includes a meansthat indicates the flow rate through the main valve for selectedpositions of the adjusting means.

8. The system of claim 1 in which the pilot control valve comprises thesole means for controlling the flow rate through the main valve.

9. The system of claim 1 in which said conduit means includes a firstportion directly connecting the pilot valve and pressure chamber andalso includes a second portion connecting the inlet side of the mainvalve to said first portion.

10. The system of claim 9 in which there is a flow restrictor in saidsecond portion.

1. A flow control system comprising a main valve with a housing havingan inlet port, an outlet port and a pressure chamber, a valve memberhaving one area exposed to the inlet port and an opposite and largerarea exposed to said pressure chamber whereby said valve member is movedtoward open and closed positions according to predetermineddifferentials in pressures of fluid in said inlet port and pressurechamber, a differential pressure device on one side of said main valveand connected thereto so that fluid passing through the main valve alsopasses through the device, said device having means to create a lowerpressure in the outlet side thereof than in the inlet side, a flowcontrol valve having a pressure responsive movable wall with one side ofthe wall connected to the inlet side of said device and an opposite sideconnected to said outlet side, a pilot valve actuated by said movablewall, conduit means connecting an upstream side of the pilot valve tothe upstream side of the main valve and to said pressure chamber, and aconduit connecting the downstream side of the pilot valve to thedownstream side of the main valve, said pilot valve including a seatmember and a plug member, said members being relatively movable forcontrolling flow between said pressure chamber and said outlet port, andadjusting means for directly moving one of said members relative to theother member for varying the amount of opening between said members whenthe movable wall is in a predetermined position.
 2. The system of claim1 in which said pressure differential device is downstream of the mainvalve.
 3. The system of claim 1 in which the pilot valve members areeach independently movable of the other.
 4. The system of claim 1 inwhich the seat member has a flow passage therethrough openable andcloseable by the plug member, the seat member is connected to theadjusting means for movement thereby and the plug member is connected tosaid movable wall for movement thereby.
 5. The system of claim 1 inwhich the pressure differential device comprises a venturi.
 6. Thesystem of claim 1 in which there is a means for adjusting the pressuredifferential transmitted by the pressure differential device to saidpilot control valve.
 7. The system of claim 1 in which the adjustingmeans includes a means that indicates the flow rate through the mainvalve for selected positions of the adjusting means.
 8. The system ofclaim 1 in which the pilot control valve comprises the sole means forcontrolling the flow rate through the main valve.
 9. The system of claim1 in which said conduit means includes a first portion directlyconnecting the pilot valve and pressure chamber and also includes asecond portion connecting the inlet side of the main valve to said firstportion.
 10. The system of claim 9 in which there is a flow restrictorin said second portion.